Some of the chords in this song have added tones, namely, a sixth and a ninth, written as 6add9. You don’t have to play these tones while strumming, so just play regular chords. In the original song the chords are arpeggiated; the added tones are played roughly like that (let’s look at the first chord in the original key): | E E6 E6 Eadd9 |.